Advice on mom living with tenant and not on lease

[Jay McAllister]

Hey everyone. Need some advice. One of my properties a younger couple is renting. They unknown to me, seem to have his mother living there with them it seems. I have had this home for a few years and couple before them zero issues. Ever since they have moved in there has been issues. First the well water smells so I send multiple ppl out and all say it is ok but they still complain, then she claimed ants were invading ( I looked they were not) then the toilet wouldn't flush for two months they told my maintenance guy I said in front of them this is first I heard of it they didn't say anything, my plumber then told me there was nothing wrong with the toilet either. Now the mother tells me yesterday she's paying the rent and is unhappy with the home for these reasons and that it is a small 2 bedroom, I told her your not on the lease and have no legal standing to live here, all after another water guy was there and told her as I stood there nothing at all is wrong with the water. Now she's  having the son who is on the lease asking for a copy of the lease, which he already has. The mother seems to be a major problem. Not sure what to do if tell her out if she is indeed living there or what to do. They are 3 months into a 12 month lease, obviously want the lease fulfilled. Thanks for your help everyone!